The present invention relates to a self-expanding vascular implant for implanting into a blood vessel, comprising a hollow-cylindrical body with a first end and a second end and a longitudinal direction, and also comprising stent springs successively arranged at a distance from one another over its longitudinal axis and circumferentially meandering, respectively, and comprising an implant material fixed to the stent springs and connecting them, the stent springs only being connected via the implant material and not between one another, and the circumferential stent springs having pointed arches facing alternately toward the proximal direction and the distal direction and having alternating vertices and lowest points, which are connected to one another by legs.
Such vascular implants are known in the prior art, e.g. from DE 103 37 739.5.
For treatment of aneurysms in arteries, it is generally known to implant intraluminal vascular implants, which are also referred to as endovascular stents/stent grafts. An aneurysm is understood as being a widening or bulging of an arterial blood vessel as a result of congenital or acquired changes of the wall. The bulging may affect the vessel wall as a whole or, as in the case of a so-called false aneurysm or so-called dissection, blood can flow from the lumen of the artery in between the layers of the vessel wall and can tear them apart. Non-treatment of an aneurysm can lead to a rupture of the artery at the advanced stage, with the consequence that the patient internally bleeds.
The self-expanding vascular implants that are used for the treatment of such aneurysms generally consist of a hollow-cylindrical metal frame, the lateral surface of which is covered with a textile or polymer film, so that a hollow-cylindrical body is obtained. For implantation, the vascular implant is radially compressed, so that its cross section is significantly reduced. Then, with the aid of an insertion system, the vascular implant is brought into the region of the aneurysm, where it is released. Due to the resilience of the metal frame, the vascular implant expands again into its original form, thereby spreading its jacket surface, which becomes clamped internally in the blood vessel proximally and distally with respect to the aneurysm. In this way, the blood can now flow through the vascular implant and further loading of the bulging is prevented.
The metal frame of such vascular implants generally consists for example of a wire mesh or of so-called stent springs successively arranged one behind the other and circumferentially meandering, which are—as the case may be—connected to one another by way of connecting supports of wire, or which are only connected to one another via the implant material. The wire mesh or the stent springs are usually of a shape-memory metal, generally of nitinol, whereby, after being introduced into a vessel, the stent springs again transition into the expanded state for release, and thereby “spread out” the vascular implant.
With vascular implants known in the prior art, in particular those that have stent springs circumferentially meandering, which are either only connected to one another by implant material, and consequently only indirectly connected, or else are additionally connected between one another by way of connecting legs or supports, there is the risk of kinking/buckling during the introduction into a vessel, and in particular whenever the vascular implant is introduced into or through a bent portion of a vessel. This kinking occurs in particular whenever the vascular implant is intended to be adapted to the natural shape of the bent vessel, and the bend is intended to run in the region of two or more stent springs arranged one behind the other: in this region, a lowest point of the one stent spring and a vertex of the stent spring arranged distally thereafter usually lie opposite one another, so that the vascular implant easily buckles here on account of the small intermediate space that lies between these two points and is only formed by the implant material.
Such kinking/buckling is extremely disadvantageous, since the regular blood flow through the vessel is no longer ensured when there is kinking, and, as a consequence, stenoses and turbulences of the blood within the vascular implant may occur or even a vessel occlusion.